Angular 7 + Ionic 4: No provider for NavController! (Clue: incorrect module name imported)

NullInjectorError: No provider for NavController!

After switching from AngularJs to Angular 7 and Ionic 4, I've came across a few new issues where led me to high dependence on StackOverflow.
For certain edge cases without a certified answer, as plus Ionic 4 is still in beta build (during my writing of this article). If SO don't has the answer, I'll have to spend more hours on the issue by diving into the error message and core library.

First thing came into my mind when I first look at the error message:

What is NavController has to do with my code while I've never imported it into any of my component. I didn't use NavController at all in my code as Ionic mentioned they are deprecated in Ionic4

After spent 2-3 days of clueless bug hunting, it's found how I imported IonicModule is the culprit!

Capital letter '@Ionic/angular' should be '@ionic/angular'

In short, the solution is to check your module name if they are written in correct case format (yes case sensitive, I've learned my painful lesson).

Quick Solution:
@Ionic/angular should be @ionic/angular

No provider for NavController

...
ERROR Error: StaticInjectorError(AppModule)[HrefDelegate -> NavController]: 
StaticInjectorError(Platform: core)[HrefDelegate -> NavController]: 
  NullInjectorError: No provider for NavController!
  at NullInjector.push../node_modules/@angular/core/fesm5/core.js.NullInjector.get (core.js:717)
  at resolveToken (core.js:954)
  at tryResolveToken (core.js:898)
  at StaticInjector.push../node_modules/@angular/core/fesm5/core.js.StaticInjector.get (core.js:795)
  at resolveToken (core.js:954)
  at tryResolveToken (core.js:898)
  at StaticInjector.push../node_modules/@angular/core/fesm5/core.js.StaticInjector.get (core.js:795)
  at resolveNgModuleDep (core.js:17656)
  at NgModuleRef_.push../node_modules/@angular/core/fesm5/core.js.NgModuleRef_.get (core.js:18345)
  at resolveDep (core.js:18716)
...

Like the error message above, Ionic4 didn't really provide very informative clue that helps debugger identify what is rootcause. So yeah, there are risks when we use beta library building our project...
I believe soon later, the error message would be clearer once it's near its official stable build release date.
There is also a slightly useful warning message obtained from browser console, posted as below

...
There are multiple modules with names that only differ in casing.
This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
Use equal casing. Compare these module identifiers:
// ... list of affected files ...
/node_modules/@ionic/angular/dist/providers/action-sheet-controller.js
/node_modules/@Ionic/angular/dist/util/overlay.js
/node_modules/@ionic/angular/dist/index.js
/node_modules/@Ionic/angular/dist/providers/action-sheet-controller.js
/node_modules/@Ionic/angular/dist/util/util.js
...

Well, the messages in debugger do shine some light about the ambiguous and conflicting module names, the list of affected files don't really tell what has gone wrong.
Hope this article could help some not-so-lucky guys out there who fell into traps set by ourselves.

Raspberry Pi: Headless Setup Notes - For beginner & pre-configuration

How to

2 solutions:

1. Create an empty file "ssh" or "ssh.txt" (case sensitive, must lower case) in the root folder of SD card created for OS installation.
2. Plug HDMI to your raspberry pi to a monitor and follow steps below

HDMI + Monitor solution

1. SSH is disabled by default (default setting of a rpi)
2. USB or through HDMI use your rpi
3. enable SSH in your raspi-config or through terminal
4. follow steps below to enable remote SSH in your rpi

Select 7 for advanced options

Select SSH

Select Yes to enable remote SSH for Headless environment

Raspberry Pi: Send Email as your personal Notifier!

Configurations

you need smtp installed, to get it, you need (smtp and mail):

  
    sudo apt-get install smtp mail
  

Setup email server configuration (edit smtp config):

  
    /etc/ssmtp/smtp.config
  

into format as below:

  
    root=your@email.com
    mailhub=mail_service_provider #for example "smtp.gmail.com:465"
    FromLineOverride=YES
    rewriteDomain=gmail.com
    AuthUser=your@email.com
    AuthPass=yourpassword
    #UseSTARTTLS=YES
    UseTLS=YES
  

Sending Email in Plaintext

  
    echo "the content of the email body" | mail -s "This is the subject" your@email.com
  

Troubleshooting

Just in case you run into Gmail authorization problems:
1. mail: cannot send message: Process exited with a non-zero status
Probably your smtp.config has it configured incorrectly

2. ssmtp: Cannot open smtp.gmail.com:465
Check if your port number is entered correctly

3. ssmtp: Authorization failed (for Gmail, if you have 2FA activated)
You might have to follow this 2FA Gmail Solution to add an app-specified password for that particular app.

Send Email with attachment (Coming soon...)

Content coming soon... (be patient)

References
Read the man page: Mail
Send file as attachment with Email
ssmtp-to-send-emails
4 Ways to Send Email Attachment from Linux Command Line
Sending Email from RPi

Wobbling Pokeball with SnapSVG

Creating SVG from ground up

If you've just gotten started, then the first dirty tips to answer your questions (which you might have in mind as a beginner):

• Yes, you can import external SVG file/code into your SnapSVG Javascript code
• SnapSVG can help writing pure SVG code from scratch (yes, for simple SVG, but I don't think this is a proper way to write your big animated SVG project from scratch)
• (my gut tells me) For large SVG project, start SVG project with editor like Adobe Illustrator or Affinity Designer (follow your preferences) then export as SVG file
• Yes, for every tiny movement/animation has to be coded from scratch (no shortcut, so try to reuse code if possible)
• Speed development - utilise handy tool like CodePen to help your development!

Steps required (when you get started):

1. (If you plan to start from scratch) Start learning adding shape/line/text into your element
2. Animating SVG (mostly achievable by using the ELEMENT.animate())

See the Pen Wobbling pokeball (Snap.svg) by trtshen chaw (@trtshen) on CodePen.

Simple SVG Project with SnapSVG, HTML is not the first priority

As you can see from the example above, there is no HTML code available. It starts right into Javascript code with Snap() and canvas size for your svg

  
    var poke = Snap(230,230)
  

Once you are done declaring required elements, the rest of the code is written to style up your elements and properly group related elements for animating purpose.

Why Group Up Elements?
As you animate element, you have to animate related elements together, so grouping them in a "g" makes our job easier to animate them altogether and more useful for chaining a sequence of continuous animations.

Thanks SnapSVG for the great tool!

Penggunaan VCS (version control system)

Kenapa VCS?

VCS adalah shortform bagi "Version Control System", ia adalah sebuah alat/perisian wujud untuk menyenangkan developer mengurus sumber pengaturcara (source code) tanpa perlunya memindah source code scare manual dari satu sistem ke sistem yang lain.

Padahal, source code sentiasa dikemas kini dan dibaharui mengikut keperluan dari semasa ke semasa, jikalau kumpulan mempunyai lebih daripada satu developer, pengurusan source code yang tidak melibatkan kegunaan alat VCS merupakan satu perkara yang sukar atau boleh dikatakan boleh mencapai tahap mustahil (jika source codenya terlibat beribu-ribu baris kod). Bagi fasa nyahpepijat (debugging) kesukaran tidak dapat dibayangkan jika tidak wujudnya alat VCS ini!

VCS sebagai pegetahuan am

Kegunaan alat/servis VCS sudah menjadi biasa dalam dunia sistem pembangunan, servis yang (bebas digunakan dan percuma) sedia ada pada internet kini:

• github
• bitbucket
• cvs (telah lama ketinggalan, boleh dikatakan tidak berguna lagi selepas kemunculan git ke dunia internet kini)

Keselamatan guna VCS

Kegunaan github/bitbucket memerlukan pengguna simpan (muat naik/upload) source code ke server github/bitbucket. Muat naikkan source code ke server github mungkin menakutkan pengguna bahawa adakah source code masih selamat disimpan pada server "orang lain".

Selepas beberapa tahun pengalaman saya guna dan simpan code atas server github, tiada sebarang masalah bernah berlaku pada source code saya.

Walau bagaimanapun, tragedi yang tidak menyenangkan hati boleh berlaku juga.  

Side note: Usaha-usaha dalam Kommuniti Opensource

Setiap developer perlu berterima kasih kepada syarikat-syarikat IT dari barat seperti Google, FB, Github... dan lain-lain lagi. Mereka telah banyak mengusahakan industri IT bagi kommuniti sumber-terbuka IT (opensource) dan menbenarkan kegunaan servis-servis mereka tanpa had (bagi aktiviti yang tidak berasaskan keuntungan sahaja). Usaha-usaha mereka telah banyak memanfaatkan developer IT memperoleh segala tutorial/artikel IT yang diperlukan atas talian.

Sebagai seorang developer di Malaysia, saya pun telah banyak menikmat usaha-usaha mereka yang sentiasa fokus pada "kemampuan developer dari kommuniti opensource". Tanpa usaha mereka, saya tidak dapat bayangkan sesiapa sanggup akan memurahkan hati pada tahap yang sama seperti apa mereka telah usahakan dalam kommuniti opensource ini. 🙏